Step 5: Pinning or Fruiting Process
The substrate bags are kept in the mushroom house for another week or so before they
are opened to check the mycelia growth. At the time of opening the bags, the bags are supposed
to be full with strong growth of mycelium. Generally, fruiting or formation of primordia starts
after 3 to 4 weeks of mycelia growth. It is better to make cross-cuts of about 2.5 cm across the
bags to allow the mushrooms to grow out. Temperature inside the mushroom house should be
increased to range of 20-28oC in order to promote fruiting. Relative humidity should between
80 - 95%. There should be adequate ventilation inside the room to lower the carbon di oxide
concentration which should be 0.08 percent or lower.
It is best to place the substrate bags about 10 cm or more above the floor. In doing so, if
ventilation is stopped, carbon dioxide accumulated near the floor will not damage the growing
mushrooms. It will also restrict the access for insect-pests. Light should be allowed for a few
hours a day by keeping doors open. Or else fluorescent lights can be turned on. Light watering
of substrate bags using a mist sprayer is recommended daily for higher yields. While watering bags, care must be taken not to overwater the bags. 3 to 4 days after opening the bags, fruiting
or pinning starts. Small pins or mushroom primordia develop as outgrowths on a rhizomorph
which gradually grow in size into the button stage, and later enlarge in to full-bodied
mushrooms. Fruits or mushroom primordia mature in 2 to 3 days once fruiting process is
initiated. Generally only one side of the substrate bag is opened at a time. In rare cases, both the sides are opened at the same time.